Notices
1973 - 1979 F-100 & Larger F-Series Trucks Discuss the Dentsides Ford Truck
Sponsored by:
Sponsored by: Moser

Let's Talk Exhaust

Thread Tools
 
Search this Thread
 
Old May 7, 2017 | 02:45 PM
  #1  
F-250 restorer's Avatar
F-250 restorer
Thread Starter
|
Lead Driver
15 Year Member
Photogenic
Liked
Loved
Joined: Mar 2008
Posts: 7,193
Likes: 387
From: Near Los Angeles
Let's Talk Exhaust

I'm coming off dual 2.5" header collectors, into a Y with a 3" out, and using 3" tube to the rear axle, out a Flowmaster 50, with a 2.5" tail pipe. I'm thinking that the gas will have cooled by the time it reaches the axle, so the smaller pipe diameter won't be a bottle neck or reduce performance.

Space is an issue and I wanted to do away with the dual pipes. The engine being a 300, both pipes are on passenger side. For clarification, I should mention that I'm changing from long tube Hedman (fitment issues, rattling) with 1.5" tubes, to a set of Clifford shorty headers with 1.625" (1 5/8")tubes. Collectors are 2.5" on both headers.

I didn't want to go with a single 2.5" tube since the hp limit is about 230, and I should be over 250. Does that sound kosher to all the exhaust experts?
 
Reply
Old May 7, 2017 | 09:47 PM
  #2  
HIO Silver's Avatar
HIO Silver
Fleet Owner
Joined: Dec 2009
Posts: 20,678
Likes: 83
From: NorCal
2.5 inch into a single 3-inch inch all the way out is acceptable. Choking it down with a 2.5 inch tail section is usually not recommended but since ya got a 300p0, the HP/TQ level is low enough not to be negatively affected.

Proceed.
 
Reply
Old May 8, 2017 | 12:43 AM
  #3  
F-250 restorer's Avatar
F-250 restorer
Thread Starter
|
Lead Driver
15 Year Member
Photogenic
Liked
Loved
Joined: Mar 2008
Posts: 7,193
Likes: 387
From: Near Los Angeles
Originally Posted by HIO Silver
2.5 inch into a single 3-inch inch all the way out is acceptable. Choking it down with a 2.5 inch tail section is usually not recommended

but since ya got a 300p0, the HP/TQ level is low enough not to be negatively affected.

Proceed.
How interesting that so many people automatically dismiss any 300 as having low hp. Let me put it this way: I have a 300 with more hp than a 352, and about equal to several stock 360's and 390's.

And since it is horse power we are concerned with, regardless of the engine it comes out of, let us approach the topic anew.

With an engine putting out about 250 hp be bothered by reducing the exhaust tube from 3" to 2.5" when the gas is more than eight feet from the engine? Has the gas cooled by then and become denser? thereby not needing the same pipe area/volume? According to the info I have gathered, max hp for 2.5 tube is 230.
 
Reply
Old May 8, 2017 | 08:37 AM
  #4  
HIO Silver's Avatar
HIO Silver
Fleet Owner
Joined: Dec 2009
Posts: 20,678
Likes: 83
From: NorCal
Cooling the exhaust gases isn't the issue... it's all about flow and restrictions.

Not discounting the 300 at all... TQ is what counts on these trucks, not HP. Your set up is fine.
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
tjcprop
6.2L V8
1
Apr 23, 2014 09:45 PM
Grendelx
Ford Inline Six, 200, 250, 4.9L / 300
3
Oct 17, 2012 12:17 PM
2006 F-150 FordSter
Modular V8 (4.6L, 5.4L)
33
Jul 6, 2012 09:38 PM
Mustang6147
Exhaust Systems
42
Oct 21, 2009 03:09 PM
superswamper
Exhaust Systems
1
Jun 22, 2003 02:15 PM




All times are GMT -5. The time now is 11:08 PM.

story-0
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level

Slideshow: The VelociRaptor Expedition gains a lift, upgraded suspension, Brembo brakes, and trail-ready equipment while retaining the stock 440-horsepower EcoBoost V6.

By Verdad Gallardo | 2026-06-12 11:01:55


VIEW MORE
story-1
Top 10 Fords at 2026 Carlisle Ford Nationals

Slideshow: Top 10 Fords at 2026 Ford Nationals

By Joe Kucinski | 2026-06-09 11:10:08


VIEW MORE
story-2
3 Best / 3 Worst Parts of Modern Ford Ownership

Based on years of owning multiple modern Ford products.

By Brett Foote | 2026-06-09 10:53:36


VIEW MORE
story-3
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

SPONSORED: From muddy boots to rain-soaked cargo, these upgrades address some of the most common frustrations Ford truck owners face every day.

By Pouria Savadkouei | 2026-06-08 18:50:34


VIEW MORE
story-4
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-5
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-6
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-7
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-8
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-9
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE